Photographic materials are generally comprised of a support which has electrical insulating properties and a photographic layer. In many cases, electrostatic charges build up as a result of contact friction with, or separation from, a surface of a material of the same or different type during the manufacturing processes or use of the photographic material. The accumulated electrostatic charge causes considerable damage to the photographic material. Most importantly, the accumulated electrostatic charge causes imperfection marks such as spots or tree-like or feather-like lines to appear when the photographic film is developed. These marks result from the photosensitive emulsion layer having been inadvertently exposed due to the discharge of the accumulated electrostatic charge prior to development processing. Such marks are usually referred to as static marks, and the commercial value of the photographic film is reduced to a considerable degree due to their presence and, depending on the particular case, the commercial value may be lost completely. The static marking phenomenon first becomes apparent upon development of the photographic film, and it is a very troublesome problem. Furthermore, these electrostatic charges can result in dust becoming attached to the surface of the film either before or after processing. Also, electrostatic charges can cause other secondary problems such as an inability to provide uniform coating.
The static marks on photographic materials, which are caused by such build up of static charge, become more pronounced when the photographic speed of the photosensitive material is increased and/or when the processing rate is increased. Static mark formation has become more likely to occur recently because of the increased photographic speeds of photographic materials and as a result of the more severe handling of the material such as during high speed coating, high speed camera operation and high speed automatic development processing. Moreover, the opportunities for handling processed photographic materials have increased in recent years and the attachment of dust has become a serious problem.
The addition of antistatic agents to a photographic material is desirable for preventing the occurrence of these problems due to static electricity. However, the antistatic agents which are used generally in other fields cannot be used without modification of the photographic materials because various specific limitations must be imposed when antistatic agents are used in photographic materials. That is to say, in addition to having excellent antistatic performance, the antistatic agents which can be used in photographic materials must not cause an adverse effect on the photographic performance. For example, the antistatic agents cannot cause an adverse effect on photographic properties such as the photographic speed, fog level, graininess and sharpness, of the photosensitive material, and the film strength or the antistick properties of the photosensitive material. Further, the antistatic agents must not increase the rate at which the developing baths for the photographic materials become fatigued, and they must not contaminate transporting rollers. Also, the antistatic agents must not reduce the strength of adhesion between the various structural layers of the photographic material. Thus, a great many limitations are imposed on antistatic agents for use in photographic materials.
One way of preventing the occurrence of problems due to static electricity is to render the surface of the photographic material electrically conductive so that the electrostatic charge is dispersed quickly before a charge can build up and discharge.
Other methods of increasing the electrical conductivity of the supports and the various coated surface layers of photographic materials have been considered in the past which include attempts to make use of various hygroscopic substances and water-soluble inorganic salts, and, for example, certain types of surfactant and polymers.
Among these materials, the surfactants are important from the point of view of antistatic performance, and these include the anionic, betaine and cationic surfactants disclosed, for example, in U.S. Pat. Nos. 3,082,123, 3,201,251, 3,519,561 and 3,625,695, West German Pat. Nos. 1,552,408 and 1,597,472, JP-A Nos. 49-85826, 53-129623, 54-159223, 48-19213, JP-B Nos. 46-39312, 49-11567, 51-46755 and 55-14417, and the nonionic surfactants disclosed, for example, in JP-B No. 48-17882, JP-A No. 52-80023, West German Patent Nos. 1,422,809 and 1,422,818, and Australian Patent No. 54,441/1959 (the terms "JP-A" and "JP-B" as used herein refer to a "published unexamined Japanese patent application" and an "examined Japanese patent publication", respectively).
However, these substances exhibit specificity according to the type of film support and differences in photographic composition and the performance aforementioned is not satisfactory. Further, it is very difficult to make use of these materials in photographic materials in practice.
Furthermore, the ethylene oxide adducts of phenol/formaldehyde condensates disclosed in JP-B No. 51-9610 have been shown to have excellent antistatic performance when used conjointly with various coating agents. However, the problems due to contamination in the development processing are not resolved with this method.
Furthermore, photographic materials which contain specified anionic surfactants and polyoxyethylene based nonionic surfactants have been disclosed in JP-A No. 53-29715, but no improvement is obtained with respect to film damage due to contamination of the development processing baths and contamination of transporting rollers.
Moreover, photographic materials which contain polyphosphazene compounds have been disclosed in JP-A No. 64-68751, but the aforementioned problems can still not be overcome even with these compounds.
Furthermore, photographic materials which contain polyacrylic based esters or amides which have polyoxyethylene groups in side chains have been disclosed in JP-A No. 63-223638 and JP-B No. 1-18408, but the antistatic performance is still inadequate and they cannot be applied to photographic materials.
Methods of processing in which the amount of water used is reduced have been used in recent years with a view to protecting the environment and economizing on water resources, as well as from the point of view of cost and for the provision of more compact processing machines. Methods in which the rate of replenishment is reduced have been used from the point of view of cost, and attempts have also been made to increase the concentrations of processing baths with a view to shortening processing times. However, increased processing bath contamination and pronounced image unevenness have become serious problems with the development of such processing methods.